In a dry etching process using plasma, an etching amount needs to be controlled. As a method for controlling the etching amount, there is a method for controlling etching time of the dry etching process. Further, as a method for controlling the etching amount, there is a method for measuring an after-etching dimension of a pattern after executing a dry etching process and controlling an etching amount by giving the measured dimension values as feedback. However, with the above two methods, it has been difficult to accurately control the etching amount.